This study is designed to investigate sex pheromone production and emission in Ixodidae so as to provide a rational basis for development of tick control strategies. The project will attempt to determine metabolic substrates used in the biosynthesis of the sex pheromone, 2,6-dichlorophenol, and possible antagonists of this pheromone activity. Candidate compounds believed to be antagonistic to 2,6-dichlorophenol synthesis or capable of disrupting its storage and/or emission will be tested by suitable means. Compounds will be inoculated into ticks or administered by topical and/or contact application and, where appropriate, to mammalian hosts. Other studies will be concerned with the apparent presence of a species-specific genital sex pheromone, which serves to prevent mating between all but conspecific partners when several species share the same host. Following the completion of studies to characterize the pheromone, efforts will be made to prepare and test extracts of attractant females to determine the chemical nature of the compound(s) serving this role. The time course of appearance, accumulation, and disappearance of sex pheromone during different phases of the life cycle of ticks will be determined.